public void Select(TransitionLibraryWindow window, Object select, TransitionLibrarySelection.SelectionType type)

We can't simply set the UnityEditor.Selection.activeObject because it might not be a UnityEngine.Object and if it is then we don't want the Project window to move to it.

So instead, we select this dummy object and Animancer.Editor.TransitionLibraries.TransitionLibrarySelectionEditor draws a custom Inspector for the target object.